P825

        Physiol Bohemoslov 1988;37(1):39-48

        Elastic properties of the rat respiratory system related to age.

        Paleček F, Ježová E.

        Institute of Pathological Physiology, Faculty of Paediatrics, Charles

        University, Prague.

        The experiments were performed on male rats of the Wistar strain under

        urethane anaesthesia (1.3 g/kg i.p.). Changes of oesophageal and

        tracheal pressures were registered in a group of 30 spontaneously

        breathing, supine rats, of 295  13 g average body weight during lung

        inflations with 1-5 ml of air. In another group of 25 rats of 70  6 g

        average body weight (young rats) we made the measurements during

        inflation with volumes 0.5-2 ml. The measurements were also performed in

        a group of 10 paralyzed, ventilated rats with 347  24 g average body

        weight and inflations 1-5 ml. Compliance of the lungs (CL), chest wall

        (CW) and of the respiratory system (Crs) was calculated from the linear

        part of the pressure-volume curve during inflation. The results

        indicate: 1. Cw is significantly (p less than 0.001) higher in young

        (134.7 ml.kPa-1.kg-1) than in adult rats (44.1 ml.kPa-1.kg-1). CL

        (related to body weight) is not significantly different in young and

        adult rats. 2. Cw is significantly (p less than 0.001) higher than CL.

        3. No difference was observed in CLs Cw and Crs between paralyzed and

        spontaneously breathing animals.